Polymerization-induced viscoelastic phase separation in polyethersulfone-modified epoxy systems.
The polymerization-induced phase-separation process of polyethersulfone (PES)-modified epoxy systems was monitored in situ continuously on a single sample throughout the entire curing process by using optical microscopes, time-resolved light scattering (TRLS), scanning electronic microscopes (SEM), and a rheometry instrument. At specific PES content a viscoelastic transformation process of phase inversion morphology to bicontinuous was found with an optical microscope. The rheological behavior during phase separation corresponds well with the morphology development. Light-scattering results monitoring the phase-separation process of systems with final phase inversion morphology show a typical exponential decay procedure of scattering vector qm. The characteristic relaxation time of phase separation can be described well by the WLF equation.
Yu
Yingfeng
Y
Department of Macromolecular Science and The Key Laboratory of Molecular Engineering of Polymer, Ministry of Education, Fudan University, Shanghai, 200433, China.
Wang
Minghai
M
Gan
Wenjun
W
Tao
Qingsheng
Q
Li
Shanjun
S